Island



UNITED sTATEs PATENT oEEioE.

TISDALE CARPENTER, OF PROVIDENCE, RHODE ISLAND.

OPERATING THE VALVES OF STEAM-EN GINES.

Specication of Letters Patent No. 25,722, dated October 11, 1859.

To all lwhom 'it may concern:

Be it known that I, TISDALE CARPENTER, of Providence, in the county ofProvidence and State of Rhode Island, have invented certain new anduseful Improvements in Devices for Operating or Working the Valves ofSteam-Engines, of which the following is a full, clear, and exactdescription, in which- Figure l is a perspective view showing the devicefor working' the valves, and one form of attachment to the cylinder of asteam engine. Fig. 2, is a vertical cross section of the same, theregulator having been turned a quarter of a revolution. Fig. 3 is anenlarged plan view showing the device for producing` the effecttechnically termed ccut off in working the valves of steam engines.

The nature of my invention and improvements in devices for operating thevalves of steam or gas engines consists in a graduated adjustable scrollshaped side cam so arranged that it may be set near to, or far from thecenter of motion, so as to vary and graduate the operation of theinduction valves to the cylinders of steam or gas engines, so as tosupply the quantity of steam required and then cut off the supply ofsteam or gas. Also in operating or traversing the said graduated cam,nearto, or far from the center of motion while the engine is in motionby connecting it to a ball governor or regulator, so as to regulate orgraduate, the supply of gas or steam, to the engine, and proportion itto the resistance or power required, and then cut off the supply ofsteam or gas, the graduated cam being so constructed as to open thevalves and hold them wide open until the required supply of steam haspassed, and then close the valves suddenly so as to cut off the furthersupply of steam to the cylinder, and thereby use the steam economicallyby supplying the steam through a port or valve that is wide open; untila sufhcient quantity of steam has passed through to generate the powerrequired, and then close the valve suddenly and cut off the supply atonce.

That others skilled in the mechanic arts may make and use my invention Iwill now proceed to describe the manner in which I have carried it out.

In the drawings, A, represents a portion of the frame or bed-piece, towhich the working parts of an engine are attached, B, is the cylinder,S, is the steam pipe through which the steam is admitted to thecylinder, and E, is the exhaust pipe through which it is withdrawn.

V, V, are the induction valves, and P, P, are puppets by which they areworked, by means of the connecting levers L, L.

In suitable bearings in the frame of the engine (which in this instanceisa horizontal one) is placed an upright shaft I; which shaft isconnected by miter gears G, G, to the horizontal shaft F, which isterminated in the drawings and model by the crank K, but in the workingengine is continued until it is connected to the main shaft of theengine by a pair of wheels corresponding in size and nature to thosejust mentioned; consequently the upright shaft will at all times agreein speed with .the main shaft of the engine.

Upon the upper portion of the shaft I, which is raised the requireddistance above the cylinder of the engine, is placed the commonly formedregulator R which is attached to and revolved by it. Immediately beneaththe regulator R is placed the disk D, (also permanently attached to theshaft) to which is connected the movable graduated scroll formed, sidecam C.

This being the device by which the combined action of working the valvesand producing the cut off, is performed, I will now explain the mannerin which it is constructed. The under surface of the disk having beenmade perfectly true and at right angles to the shaft upon which it isplaced, has a dovetailed groove J, cut directly across its center aslide H, of corresponding form and fitted to move easily in the groove,is placed therein and its motion back and forth confined within certainlimits by the slot M, through which the upright shaft I passes. At oneend of this slide the above mentioned cam C, is permanently fixed insuch a manner that its convex edge agrees with and becomes concentricwith the disk when the cam is carried as near to the center of the diskas the slide will permit.

On the upper side of the slide H, is attached a small block b, which bymeans of a slot in the end of the slide and the correspondingindentations in the edges of the disk is made adjustable so that it maybe fixed at a greater or less distance in proportion to the position ofthe cam C, from the center of the disk D, (the object of thisadjustability will be explained hereafter,) to

the inner end of this block is attached by its centers a small roll r,through which passes the pin p, which pin being a continuation of one ofthe arms of the regulator, thereby forms a continuous, as well asadjustable and easily movable connection between the regulator andscroll shaped cam C.

Under the disk D, and at opposite points of its circumference are thepuppets P, P, supported in bearings so as to move freely up and down ina vertical direction, and in a cavity in the frame where their lowerends are placed, are spiral springs the tendency of which is to keep thepuppets raised up against the under surface of the disk, which is theposition when the valves V, are closed. There is also another disk D',of similar form placed on the lower part of the upright shaft I which bya similar system of levers and puppets work the exhaust valves of theengine; with the difference in its motion that as the exhaust valves arealways required to be opened and closed at the same point in therevolution of the engine without regard to the speed at which it isrunning, so I am enabled to dispense with the adjustable scroll cam andsupply instead a fixed side cam.

Having explained the form and construction of the devices employed in myinvention, I will now explain the manner in which they operate toproduce the effect of cutting off the steam from the cylinder of theengine at any desired point in its revolution, said point being governedentirely by the speed of the engine.

It will be seen by reference to the enlarged plan view Fig. 3 of thescroll cam and disk, that the cam is represented as being carried asnear to the center of the disk as the slide will allow, that being theposition in which it is naturally placed by the gravity of the balls ofthe regulator when the engine is at rest, or moving so slowly as not toexpand them by centrifugal force. Now suppose the disk to be revolvingin the direction of the arrow (see Fig. 8) it would carry the cam C,over the ends of the puppets P P', in the line designated by the arrow,consequently the puppet P', is pushed down and its corresponding valveopen during such part of a revolution as is contained between l, and l',which is equivalent to nearly the entire stroke of the engine therebyadmitting steam at its full pressure during all the time that it will beavailable in moving the engine.

As the engine moves faster the centrifugal force expands the balls ofthe regulator and as they move outward from the center, they carry theslide and its attendant cam until it brings the line 2 in the sameposition concentrically with the disk as the line marked by an arrow. Itwill now be seen that although in its revolution it will strike thepuppet P', at the same point on the disk to open the valve, it willrelease it a little sooner or that it will drop 0H at 2', and so on inthe same manner the faster the engine runs and thel greater theexpansion of the balls of the regulator the farther is the cam C removedfrom the center, the puppet dropping off and closing the valve atshorter and shorter intervals, as the points 3' 4' 5' 6' 7 8' arereached and placed in position concentric with the circumference of thedisk.

If the speed of the engine should be so great as to still expand theregulator beyond this last point the cam C, would be carried out so faras to revolve in a circle greater in extent than the points of the)uppets and of course would then have no e ect upon them, and so reducethe speed of the engine by giving it no steam at all until the balls ofthe regulator are collapsed sufliciently to bring the cam C, againtoward the center.

Again it will be seen by examining the outline of the cam C, that onaccount of the concavity of its inner edge the lines l, 2, 3, 4, 5, 6, 78, although made with equal radius drop off at greater distances nearthe center of the concave edge than they do at its extremities; theeffect of which is to make the engine more sensitive to the regulator atthis point, which can be made to coincide with the point on the camcorresponding to t-he average speed intended to be maintained, for it isevident that the greater the distance between any two points (as 5', and6', compared with l', and 2', which are between lines radially equal) sothe less the regulator will have to expand or contract to sensiblyshorten or lengthen the period which the valve is kept open.

I now come to the block Z), before mentioned which in the presentinstance forms the connection between the regulator and the slide whichwas before stated to be adjustable. The object of this adjustment is toenable the engineer readily to change the point at which the averagespeed of the engine cuts off the steam: thus a given speed of theregulator causes it tovexpand to a given extent. This expansion carriesthe cam C, out so that the line 4 (for example,) is in contact with thepuppets P, P', corresponding to a little more than half stroke, at whichthe average speed of the engine cuts off. Now if the screw s, whichholds the block Z2, is loosed and the block moved on the slide H, towardthe center of the disk D, and made fast, then the same speed andconsequently the same expansion of the regulator which has beenmaintained before would carry the cam C, out to a greater distance andthe engine would cut ol1 at a lesser part of the stroke; or vice versaif the block b, was moved outward from the center the cam would becarried a lesser distance, and the izo engine Would cut off later or ata greater portion of the stroke, thereby making the engine not onlyautomatic when arranged to run at a given speed With a given pressure ofsteam, but also capable or' having that automatic ability to regulateitself, extended over a great range of variable conditions at the Willof the engineer. I Would also remark that it is not a necessity that theadjustable block b, should be attached to the regulator in the precisemanner shovvn in the model; but that it may be attached by properlyointed rods to the center slide of the regulator or in any other Waythat may be convenient to the' builder.

When the cam is used Withouta regulator, a set screw may be put in thedisk D, to hold the slide II, so that the cam may be released andadjusted by hand when the engine is stopped. It will also be understoodthat this plan of Working the valves of steam engines is not coniined toa horizontal engine alone, nor to any peculiar form of valve, but may beeasily adapted to an upright engine, or to most of the forms of thesteam valves in common use.

I believe I have described and represented the improvements Which I havemade so as to enable any person skilled in the art to make and use themI vvill noW state What I desire to secure by Leters Patent, to Wit.

l/Vhat I claim as my invention and improvements in devices for operatingthe induction valves of steam or gas engines, so as to supply andgraduate the steam or gas in proportion to the power or resistance to beovercome, and cut ol the steam or gas When it is no longer required, is-

The adjustable graduated scroll shaped side cam, so arranged, as to betraversed and adjusted by a regulator or governor While the engine is inmotion substantially as described; or adjusted and fixed or set by handWhile the engine is stopped.

TISDALE CARPENTER.

fitnesses HENRY MARTIN, ALBERT M. HEWITT.

